As a celebrity, she's probably accustomed to having the truth mutate out of form occasionally. So it's understandable that Sienna Miller was keen to put the latest rumours about her to bed - almost literally.

Speaking at the launch of her new film, Live By Night, she rubbished gossip that she cried after filming sex scenes with hunky co-star Ben Affleck.

In fact, she went one better and clarified the facts on Wednesday - stating that it was such good fun, she shed tears of laughter.

Chatting on the red carpet at London's BFI Southbank, she said: "We had a day of shooting - it was a montage of different scenarios - but I've just heard there's all this stuff about me crying."

Exasperated, she added: "I mean, I was laughing - they were tears of laughter. I wasn't weeping!"

She later branded the claims "irresponsible journalism" and added: "It's always the same!"

Sienna and Ben share some rather saucy moments in the movie (Image: Warner Bros)

It comes after she told E! that a nine-hour shoot left her having to leave the set with tears running down her face because it was "hysterical".

She added: "Ben and I are like brother and sister, thank God, so there was no awkwardness. There was just a lot of stupid giggling. He's very professional - I am not, but he is," she revealed.

"There was a montage in the script saying we did it everywhere: in the car, in the bar...I was like, 'That's an entire day of just love scenes! OK. How do we do this?'

"Obviously, by the time nine hours of it has gone past, I was shaking with tears running down my face. I mean, I can't tell you – but you have to laugh. Ben is just professional. It is what it is."